Owner’s Manual

Black plate (22,1)
GMC Yukon/Yukon XL Owner Manual - 2011
5-22 Instruments and Controls
To prevent more serious damage to
the vehicle:
.
Reduce vehicle speed.
.
Avoid hard accelerations.
.
Avoid steep uphill grades.
.
If towing a trailer, reduce the
amount of cargo being hauled
as soon as it is possible.
If the light continues to flash,
when it is safe to do so, stop the
vehicle. Find a safe place to park
the vehicle. Turn the vehicle off,
wait at least 10 seconds, and
restart the engine. If the light is still
flashing, follow the previous steps
and see your dealer for service as
soon as possible.
Light On Steady: An emission
control system malfunction has
been detected on the vehicle.
Diagnosis and service might be
required.
The following may correct an
emissions system malfunction:
.
Make sure the fuel cap is
fully installed. See Filling the
Tank on page 9‑72. The
diagnostic system can determine
if the fuel cap has been left off or
improperly installed. A loose or
missing fuel cap allows fuel to
evaporate into the atmosphere.
A few driving trips with the cap
properly installed should turn the
light off.
.
Make sure the electrical system
is not wet. The system could
be wet if the vehicle was driven
through a deep puddle of
water. The condition is usually
corrected when the electrical
system dries out. A few driving
trips should turn the light off.
.
Make sure to fuel the vehicle
with quality fuel. Poor fuel quality
causes the engine not to run as
efficiently as designed and can
cause: stalling after start-up,
stalling when the vehicle is
changed into gear, misfiring,
hesitation on acceleration,
or stumbling on acceleration.
These conditions might go away
once the engine is warmed up.
If one or more of these
conditions occurs, change
the fuel brand used. It will
require at least one full tank
of the proper fuel to turn the
light off.
See Recommended Fuel on
page 9‑68.
If none of the above have made
the light turn off, your dealer can
check the vehicle. The dealer
has the proper test equipment
and diagnostic tools to fix any
mechanical or electrical problems
that might have developed.